The “guns don’t kill people, people kill people” argument applies to words too. We can’t pin the actions of George Zimmerman, the Florida crime-watch volunteer who shot and killed 17-year-old Trayvon Martin for the crime, essentially, of walking while black in a gated community, on politicians, pundits and pastors who stoke fear and hatred of racial, ethnic or religious outsiders.

But still.

These are ugly times, a combination of historical circumstances — the election of our first African-American President, the cataclysm of the worst economic downturn since the Great Depression — having greatly inflamed anger, resentment, distrust and out-and-out paranoia among the parts of our population most vulnerable to racist and nativist appeals. Add to this the freedom from shame granted to those who peddle and purchase hatred on the Internet and a right-wing media culture that runs on hotheaded outrage, and you have a perfect storm of conditions in which sentiments once deemed socially unacceptable can be redeemed as a push back against what’s “politically correct” (as Newt Gingrich put it in the South Carolina debate when he defended his description of Barack Obama as the “food-stamp President”).

We’ve made a sacrament of freedom of expression — no matter how heinous — along with our freedom to own and shoot guns, but right now the presumption of reasonableness and responsibility that accompany those rights has been sorely tested. The margin of permissibility for gun bearing and hate spewing has been so grossly radicalized that since the passage of their state’s 2005 “stand your ground” law, it’s been legal for Floridians to “shoot first” anytime, anywhere that they believe themselves or others to be in great danger or when they suspect a violent felony is going to be committed.

And this week, it was possible for former Senator Rick Santorum, on the campaign trail in Baton Rouge, La., to allow himself to be blessed by a pastor who’d just screamed that anyone who didn’t share his vision of America as a “Christian nation” should just “get out!”

Santorum defended himself by essentially saying he’d spaced out on the more problematic moments in the speech. “I wasn’t quite listening to everything,” he told reporters, and, in all fairness, video of the event does show him looking less than spellbound. Problem is, though, there are a lot of other people who pay rapt attention when prominent speakers preach hate. And when you get the explosive combination of exposure to hate speech, access to guns and mental unbalance, you are almost fated to have fatalities. (“Halfway between the lunatic and the terrorist” is the phrase a French intelligence expert used this week to describe Mohammed Merah, the Toulouse man believed to have shot three French soldiers, three Jewish children and a rabbi in southwestern France in recent days.)

In any country, at any time, unfortunately, there will be a certain population of people whose views and mental soundness border on lunacy. At times of stress — and economic conditions in the U.S. in the past few years have certainly led to toxic levels of stress — these people can come unhinged. Make guns available to them, let hate speech thrive uncondemned all around them, and you get Trayvon Martin, armed with Skittles, dead in the street.